Bayesian geoacoustic inversion in shallow water with vertical coherence of ship-radiated noise

Abstract

Spatial structure of underwater acoustic field depends strongly on the geoacoustic properties of the seabed. The geoacoustic parameters can be estimated using the spatial coherence dominated by a single broadband source. In this paper, geoacoustic inversion of a shallow water environment is carried out using the vertical coherence of ship-radiated noise at a close range. Data were measured in an experiment in the South China Sea, and the vertical coherence is extracted from a single hydrophone pair in the vertical line array. The closest point of the passing research ship approach is determined first, and then the broadband coherence curves are extracted as the input for the inversion algorithm. Due to the lack of an appropriate parametrization, the trans-dimensional inversion method combined with the auto-regressive error model is adopted in this paper. The inversion results show that the sound speed is the most sensitive, followed by the density, and then the attenuation coefficient is the least sensitive, which is consistent with previous works. The data error hypothesis is verified via a posterior examinations.